Comparison of o-octopamine and related phenylethanolamines as substrates for norepinephrine N-methyltransferase.
o-Octopamine was a substrate for rabbit adrenal norepinephrine N-methyltransferase with lower affinity than the position isomers m-octopamine and p-octopamine. The order of substrate affinity for monochloro or monohydroxy phenylethanolamines was para greater than meta greater than ortho. With phenylethanolamine and ring-hydroxylated phenylethanolamines, primary amines were better substrates than were N-methyl secondary amines. N-Methylation might be a metabolic pathway for o-octopamine, reported to occur in mammalian tissues.
D000311:Adrenal Glands / Q000201:enzymology; D000818:Animals; D004983:Ethanolamines / Q000378:metabolism*; D066298:In Vitro Techniques; D007536:Isomerism; D007700:Kinetics; D008745:Methylation; D009655:Octopamine / Q000378:metabolism*; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism*; D011817:Rabbits; D013379:Substrate Specificity
D004983:Ethanolamines; D009655:Octopamine; C005332:N-phenylethanolamine; C028435:2-octopamine; D010625:Phenylethanolamine N-Methyltransferase